Standard on older boards and many current clones. It operates at 57600 baud and has a known "watchdog timer" bug that can cause boards to enter a reset loop.
You typically do need to manually download a separate .hex file. The official bootloader files are already bundled with the Arduino IDE . arduino nano bootloader download
The Arduino Nano is one of the most popular microcontrollers for hobbyists, but it is notorious for bootloader issues—especially with cheaper "clone" boards. Whether your board is "bricked" or you simply want to upgrade to the faster version, this guide covers everything you need to know about the Arduino Nano bootloader download and installation process . What is the Arduino Nano Bootloader? Standard on older boards and many current clones
This is the easiest way to "re-download" and flash the bootloader onto your Nano. You will need a second, working Arduino (like an Uno or another Nano) to act as the programmer. Connect your working Arduino to your computer. In the Arduino IDE, go to File > Examples > ArduinoISP . Select your working board under Tools > Board . The official bootloader files are already bundled with